Domestic animals, and especially cats and dogs, are subject to urinary disorders that may or may not be accompanied by stones, consisting of ammonium magnesium compound phosphates (struvite) or of calcium oxylates.
Cats are physiologically predisposed to having concentrated urine, due to their desert origin and to their relative lack of interest in taking on board water.
In dogs, the recurrence of urinary stones is observed when an intercurrent disease increases the risk of urinary infection, a factor which promotes the formation of struvite stones, or in dogs which do not drink very much.
Kidney stones consist predominantly of calcium salts and more rarely of struvites. The latter can be dissolved by means of a diet that induces an acidic urinary pH (pH less than 6). Calcium oxylate stones are currently impossible to dissolve and they must be extracted from the bladder surgically.
The first recommendation given to individuals suffering from urinary stones is to drink more in order to dilute the urine. This dilution acts at two levels: first, by reducing the electrolyte concentration in the urine, and then by increasing micturition frequency and therefore reducing the amount of time spent by the urine in the bladder.
In animals, the most difficult thing is to increase spontaneous drinking, in particular in cats which generally drink only 30 millilitres of water per kilo of body weight.
The provision of a moist food makes it possible to induce drinking in an animal that does not drink very much, but it is not sufficient, either because it does not cause enough water to be ingested, or because it does not sufficiently increase diuresis.
Animals exhibiting a urological syndrome are often obese or carry excess weight, in particular cats. The provision of fibres in considerable amount in the food is a solution for diluting the energy density of the ingested material, but can increase the share of faecal water rather than the frequency of micturition. Moreover, the provision of a food with a high energy density is not desirable (risk of obesity due to overconsumption) but is currently virtually obligatory so as not to increase faecal water.
Thus, when it is desired to treat or prevent urinary disorders, and in particular recurrences of urolithiasis, the provision of a moist food is preferable, but it is not sufficient, may not be accepted by the animals, or even may induce an additional pathology (excess weight, obesity) if the amount distributed is poorly controlled.
There therefore exists today a need for a composition that promotes the amount of water that is drunk, which would at the same time promote urinary excretion, while at the same time not inducing gastrointestinal problems and allowing dilution of the energy content of the ingested material.